This invention relates to the production of human antibodies which are type specific and directed against Pseudomonas aeruginosa.
Pseudomonas aeruginosa is a highly virulent pathogen which infects patients receiving immunosuppressive therapy or suffering from severe thermal burns or other serious injuries, cystic fibrosis, or neoplastic diseases. Mortality from P. aeruginosa has been reduced as the result of such therapeutic agents as mafenide acetate and silver salts which inhibit bacterial colonization of the burn wound surface, potent antibiotics for treating bacteremia, and barrier isolation to minimize contact of the patient with hospital flora. Such agents, however, have only proved partially successful in controlling the morbidity and mortality associated with Pseudomonas infections.
Recently, researchers have found that specific antibodies constitute a critical immunologic defense mechanism against Pseudomonas disease; therefore, vaccines have been administered to patients in attempts to increase antibody titers in the patients. No non-toxic vaccines have been found to date which are particularly effective against the pathogen.
It is not yet clear what components of P. aeruginosa are responsible for its virulence. Many different types of infections are recognized, from acute localized eye infections and chronic lung infections to generalized systemic infections and septicemia. Several lines of evidence, however, suggest that lipopolysaccharide (endotoxin) (LPS) contributes substantially as a pathogenic factor. These include the toxic nature of P. aeruginosa LPS (Pennington et al., Am. J. Med., 58, 629-636 (1975)), and the fact that circulating D antibodies to LPS are shown to prevent or attenuate some of the adverse effects of LPS in experimental models (Cryz et al., Infect. Immun., 40, 659-664 (1983); Young et al., J. Clin. Invest., 56, 850-861 (1975)). Pollack et al., J. Clin. Invest., 63, 276-286 (1979) concluded from their studies that serum antibodies to LPS found in most patients with P. aeruginosa septicemia were correlated with patient recovery.
Numerous studies have indicated that immunoglobulin G (IgG) antibody to LPS is protective in experimentally infected animals (Cryz et al., supra; Moody et al., Infect. Immun., 21, 905-913 (1978)), and more so when combined with an antibiotic (Cryz et al., supra). A heptavalent vaccine containing LPS of the seven Fisher-Devlin-Gnabasik immunotypes of P. aeruginosa (Fisher et al., J. Bacteriol., 98, 833-836 (1969)) was found to be effective in inducing antibodies in humans. See Kohler and White, J. Infect. Dis., 136, 112-116 (1977). Attempts to immunize patients at high risk of P. aeruginosa infection with this vaccine, however, have been only moderately successful due in part to the potent endotoxin activity of LPS. Local and systemic adverse reactions to endotoxin, including fever, malaise, and pain at the site of injection, can limit vaccine dosage. See Pennington et al., supra.
Collins et al., J. of Trauma, 23, 530-534 (1983) disclose a test of a commercially available human IgG in burned mice for activity against the seven immunotypes of P. aeruginosa and an additional strain. The human IgG was not effective against imaunotypes 5 and 6 but was protective against immunotypes 1-4 and 7. In addition, Cryz et al., Infect. Immun., 39, 1072 (1983) and Sawada et al., J. Infect. Dis., 150, 570 (1984) disclose work suggesting that type-specific anti-P. aeruginosa antisera and mouse monoclonal antibodies can reduce the lethality of these bacteria in the burned mouse model. Hancock et al., Infect. Immun., 37, 166-71 (1982), Mackie et al., J. Immunol., 129, 829-32 (1982) and EP 101,039 also disclose monoclonal antibodies against P. aeruginosa.
There is a need to develop human monoclonal antibodies for passive immunotherapy of patients infected with P. aeruginosa.